Anatomical complexities for root canal Flashcards
How many root canals do upper anterior teeth typically have?
One
How many root canals do upper 4s have and where are they?
2 - buccal and palatal
How many root canals do upper 5s have?
One
How many root canals do upper 6s typically have and where are they?
4, MB1, MB2, P, D
How many root canals do upper 7s usually have?
3
How many root canals do lower anterior teeth have typically?
One
How many root canals do lower premolars typically have?
One
How many root canals do lower molars have typically?
3
What overall shape is the pulp generally?
Oval
Irregular anatomy of lower incisors
Up to 41% have a second lingual canal
Irregular anatomy of lower 4s
25% have 2 canals, 0.5% have three canals
Irregular anatomy of upper 4s
6% have three canals
Irregular anatomy of upper second premolars
40% have a single root canal, 58% have 2 canals
Irregular anatomy of upper 6s
91% have MB2 and 72% have a separate apical foramen
What is the prevalence of c shaped canals?
1% of lower 6s, 3% of lower 7s, increases to 30-42% in Korean populations
What is Ahmed et al’s classification of root canal anatomy?
NTNO-C-F where N is number of roots, TN is tooth number (FDI), O is orifice, C is canal and F is foramen
What do we use to assess curvature of the roots?
Schneider angle
How to calculate the Schneider angle?
Draw a line parallel to the long axis of the tooth in the coronal third. Draw a line from the apical foramen to intersect the first line. The angle formed is Schneider angle.
What Schneider angle indicates an I form canal curvature?
Less than 10°
What Schneider angle indicates a J form canal curvature?
10-30°
What Schneider angle indicates a C or S shaped canal curvature?
Over 30°
What are c shaped canals?
Cross sectional shape similar to the letter c in which there is a single c shaped root or where Mesial and distal canals communicate (or remain separate) due to fusion of the mesial and distal roots.
Which teeth are more prone to c shaped canals?
Lower 7s
What is concrescence?
Fusion of roots of at least two teeth by cementum
What is dens evaginatus?
Developmental anomaly resulting in the formation of an accessory or talon cusp
What is dens invagination?
Developmental anomaly that results in an invagination of the enamel organ into the dental papilla prior to the calcification of the dental tissues
What is an enamel pearl?
A focal mass of enamel located apical to the cementoenamel junction.
What is gemination?
“Twinning”; when a single tooth germ attempts to divide, resulting in the incomplete formation of two teeth; the tooth usually has a single root and root canal.
What is a palatal gingival groove?
Developmental anomaly that is usually found on the palatal aspect of the root of a maxillary incisor tooth. Usually extends over cingulum and extends down onto the root surface.
What is tooth fusion?
Double tooth due to the union of two adjacent tooth germs
What is root dilaceration?
Deformity characterised by displacement of the root of a tooth from its normal alignment with the crown. May occur due to injury during tooth development.
What is radix entomolaris / paramolaris?
Supernumerary root in a mandibular molar, usually located distolingually (entomolaris) or mesiobucally (paramolaris)
What is taurodontism?
Change in tooth shape due to failure of Hertwig’s epithelial root sheath to invaginate at the correct horizontal level. Enlarged pulp chamber, apical displacement of pulpal floor, no constriction at the level of the CEJ.
What are the laws of endodontic access?
Centrality, concentricity, colour change, orifice location (2), symmetry (2)
What is the law of centrality for endodontic access?
The pulp chamber of every tooth lies in the centre of the tooth at the level of the CEJ.
What is the law of concentricity for endodontic access?
The walls of the pulp chamber are concentric to the external outline of the tooth at the level of the CEJ.
What is the law of colour change for endodontic access?
The colour of the pulp chamber is darker than the surrounding walls.
What are the two laws of orifice location for endodontic access?
Orifices of the root canals are always located at the junction of the walls and floor. The orifices of root canals are located at the ventrices of the floor-wall junction.
What are the two laws of symmetry for endodontic access?
Excluding maxillary molars, canal orifices are equidistant from a line drawn in a mesial distal direction through the centre of the pulp chamber floor. Excluding maxillary molars, the canal orifices lie on a line perpendicular to a line drawn in a mesial distal direction through the centre of the pulp chamber floor.
Give three different types of endodontic access cavities.
Ninja, conservative, traditional
Which teeth have MB2?
Upper molars, 6s more frequently than 7s
How to find MB2?
It is often covered by a shelf of dentine so remove dentine carefully along a line from MB1 to the palatal canal.
